This should have been [<body>].  denotes an optional literal string,
and <> denotes a required arbitrary string. Together they denote an
optional arbitrary string.
5493af8..f0a0c5a master -> master
Open the compose window to send a new email. The new email will be sent with
the current account's outgoing transport configuration. For details on
configuring outgoing mail delivery consult *aerc-config*(5).